Diarrheal diseases such as cholera and dysentery kill about a half million people each year, most of them children. Diarrhea is most often a result of unclean water, unsafe sanitation, or poor hygiene.

Strong, healthy people can recover from diarrhea in a few hours or days at most. However, individuals weakened by malnutrition or sickness often cannot recover and start losing large amounts of fluids and salts. Without treatment, this may continue until they actually die of dehydration. Children become dehydrated faster than adults.

The treatment for diarrhea is surprisingly simple. Called Oral Rehydration Therapy (ORT), it is a mixture of water, salt, and sugar that replenishes the lost fluids in the body. This basic treatment has helped reduce diarrheal deaths by about two-thirds in recent decades. It is perhaps the height of human tragedy that still so many parents must watch a son or daughter die of diarrhea when the cure is so simple and so inexpensive.

Sources: UNICEF, World Health Organization (WHO), Rehydration Project.

Note: The map display above is representational only and does not show the names and faces of real people. The photographs are computer composites of multiple individuals.